Gauging method and means



Jan. 12, 1943. K. w. CONNOR ETAL 2,308,356-

GAUGING METHOD AND MEANS filed Oct. 3. 1939 ZShets-Sheet 1 HVVENTORS.

' Jan. 12,1943. K w. cONNoR ETAL 2,308,

GAUGING METHODQANIQY MEANS Filed Oct. 3, 1959 2 Sheet s-Sheet 2 Patented Jan. 12, 1943 GAUGING METHOD AND MEANS Kirke W. Connor, Detroit, and Douglas T. Peden, Ann Arbor, Mich, assignors to Micromatic Hone Corporation, Detroit, Mich, a corporation of Michigan Application October 3, 1939, Serial No. 297,736

9 Claims.

Our invention relates to honing tools and methods, and particularly to a method and device for accurately gauging the inside diameter of a cylinder during the machining operation and interrupting the operation when a desired diameter has been reached.

Heretofore when machining a cylinder it was necessary to stop the machining operation, remove the tool from the bore, and thereafter measure the bore diameter. While a gauge plug was successfully employed with tools which operated within the bore, such gauge plugs are impractical when employed with a honing tool because of the tool reciprocation beyond both ends of the cylinder. When practicing our invention we employ'a caliper element adjacent to the cylinder to be measured, set substantially to the desired diameter of the cylinder. The honing tool passes through the caliper element as it hones the wall of the cylinder, being reciprocated in such manner as to have approximately one-half of each end of the tool extended beyond the top and bottom of the cylinder respectively during each cycle of reciprocation. The honing tool is rotated as it is reciprocated so that the spaced stones on the tool body, for the purpose of measurement, may be considered as a solid surface. As the stones expand during the abrading operation they approach the measuring shoes of the caliper element until the hole is substantially to diameter when the shoes'of the caliper element are engaged. This engagement occurs with suficient pressure at the time the diameter desired in the cylinder is reached to operate a cam and a switch to interrupt the honing operation by contracting the abrading stones of the tool and removing the tool from the cylinder.

The caliper element is preferably made of two hinged arms pivoted together, having the ends spaced from each other and connected by a strip of spring material which is twisted to provide a predetermined torsional stress which causes the unwinding of the strip when the ends of the calipers are forced apart. This unwinding of the strip rotates a cam carried thereby which operates the switch to terminate the machining operation. The shoes provided on each arm of the caliper element are preferably made of tungsten carbide or similar extremely hard material which is substantially impervious to the action of the abrasive material of the honing stones.

The caliper may be mounted on the workpiece, but preferably is attached to a sleeve disposed above the workpiece in alignment with the cylinder thereof for the purpose of guiding the tool when moved out of the cylinder. When so supported, the calipers become a permanent part of the machine and no attention is required for controlling its operation since the circuit of the machine and the switch is so interrelated as to interrupt the operation of the honing tool by throwing the starting switch to off position which permits the circuit to the switch operated by the caliper element to open which occurs as soon as the honing elements are collapsed.

Accordingly, the main objects of our'invention are; to provide a, device for measuring the diameter of an expandable tool for the purpose of measuring the diameter of the cylinder being machined thereby; to measure the internal diameter of a cylinder by measuring the diameter of the tool which periodically projects therefrom during the machining operation; to interrupt the operation of a honing machine when the tool thereof has machined the cylinder to a desired diameter through the engagement of the abrading elements thereof with a caliper element disposed in alignment with the cylinder; to have a reciprocating, expandable tool operate a caliper element when the abrading stones of the tool have expanded to the diameter desired for operating a switch which interrupts an electrical circuit to thereby interrupt the machine operation; and in general, to provide a device for measuring the external surface of a tool as it hones the internal surface of a cylinder, which is simple in construction, positive in operation, and economical of manufacture.

Other objects and features of novelty of our invention will be either specifically pointed out or will become apparent when referring, for a better understanding of our invention, to the following description taken in conjunction with the accompanying drawings, wherein:

Figure 1 is a broken view of a tool, associated with a machine and workpiece illustrated in sections, embodying the gauging device of our invention;

Fig. 2 is a sectional View of the structure illustrated in Fig. 1, taken on the line 22 thereof;

Fig. 3 is a sectional view of the structure illustrated in Fig. 2, taken on the line 3--3 thereof;

Fig. 4 is a sectional view of the structure illustrated in Fig. 3, taken on the line 4-4 thereof;

Fig. 5 is a sectional view of the structure illustrated in Fig. 3, taken on the line 5-5 thereof, with the switch operating cam in switch open position;

Fig. 6 is a view of the structure illustrated in Fig. 5, with the switch operating cam in switch closed position;

Fig. 7 is a diagrammatic view of the operating elements and circuit employed with the gauging device illustrated in Figs, 1 to 6 inclusive, and;

Fig. 8 is a view of structure similar to that illustrated in Fig. showing a modified form thereof.

In Figure 1, we have illustrated a cylinder is which is to be honed to a desirable diameter by a honing tool II which is driven in rotation and reciprocation within the cylinder. The honing body for the tool is provided with a plurality of abrading stones I2 which are movable radially to contracted and expanded position by mechanism not herein illustrated but which is wellknown in the art. Medially of the abrading stones i2 wiper guides l3 are employed for positioning the tool body within the cylinder when the abrading stones are collapsed to a less diameter than that of the guides. A guide sleeve Hi is disposed aligned with the cylinder which the abrading body of the tool H is drawn when the body is withdrawn from the cylinder Id, The wiper guides I3 engage the surface of the sleeve Mv and thereby retain the toolbody in position while preventing any material abrading of the surface contacted thereby. A coolant my be supplied to the stones l2 during the abrading operation through an orifice l5 in the supporting casting l6 and in communication with one or a plurality of apertures IT in the .sleeve M.

The gauging device to be employed in combination with the tool I I for externally measuring the internal diameter of the cylinder H3, embodies a pair of arms is and 2| pivoted together on the stud 22 which supports the arms on the sleeve I4 as illustrated in Fig. 1. The arms i9 and 21 when pivoted together assume a horseeshoe shape asillustrated clearly in Fig. 2. The end 523 of the arm i9 and the end 24 of the arm' 2! are split at 25, the end 23 being provided with a screw 26 which clamps the two split sections.

The end 23 of the arm l9 has athreaded aperture 27 communicating with the slot 25. An adjusting screw 28 is threaded within the aperture 21, which screw has a slot 29 in its side. Within the adjusting screw 28 a spring retaining spool 3! is mounted, having a slot therein in which a strip of spring material 32 is secured by a pin 33 which also extends through the wall of the adjusting screw 28.

The opposite end of the strip of spring material 32 is pinned to a spool 34 disposed on the end of an adjusting knob 35 having an index face 35 adjacent thereto. The spool 3 3 is mounted within an aperture 3'! on'the end 2 2 of the arm 2| in communication with the slot 25 in the arm. A screw 38 on the'arm draws the split portion of the end 26 together to clamp the portions about the spool 34. By adjusting the screw 28 through the insertion of a screw driver in the slot 39 in its end the distance between the ends of the arms [9 and 2| is adjusted to have .the device conform to the diameter of the cylinder to be gauged.

The arm I9 is provided with an extension 4| projecting inwardly toward the arm 2! and forwardly at 42 to be disposed substantially medially between the ends 23 and 24 of the arms. The. portion 42 is slotted at 63, the spaced portions being provided with apertures Lid, the walls of which are sloped to form annular knife edge supports 45 for a shaft 46. In the slot 53, a split cam 51. is mounted on the shaft 46 and supported by the knife edge guides 55. The strip of spring it! into compensated for.

material 32 is disposed in a slot 48 in the shaft 45, being clamped therein when a set screw 49 in the cam 4'! draws the split portions thereof about the shaft 46, which being split is clamped onto the strip of spring material 32.

A bracket 5| is mounted upon the laterally extending portion 4| of the arm i9 having a switch 52 bolted or otherwise secured thereto. The switch has a plunger 53 which rests upon the surface of the cam 4'! to be in circuit open position when in the position illustrated in Figs. 5 and 7, and in circuit closed position when moved inwardly through operation of the earn, as illustrated in Fig. 6.

The arms l9 and 2| have a shoe 54 mounted thereon with their arcuate faces 55 disposed on a circle substantially that of the cylinder to .be measured. The material of the faces 55 is preferably tungsten carbide, or other hard substance which is not appreciably abraded by the soft stones employed in the honing tool. The spring strip 32'is adjusted. in length through the adjustment of the screw 28 to have the faces 55 of the shoes 54 spaced slightly less than the diameter of the cylinder to be finished by the honing tool. A twist is placedin the strip 32 through the rotation of the knob 35 to bring the cam 41 into that relationship with the plungor 53 of the switch 52 as illustrated inFig. 5.

The honing operation is started and continues until the abrading of the cylinder wall has progressed to substantially that producing the diameter desired. At that time the abrading stones ill contact the faces 55 of the shoes 54 each time the tool is reciprocated and moved from the top end of the cylinder l0. In the abrading operation it is the custom to employ a length of stroke such that the stones will project a material amount from eachend' of the cylinder which amount is preferably less than one-half the length of the stones. In'thismanner, each time the stones are moved from the top of the cylinder in while the tool is rotating, the faces 55 will be engaged thereby until the expanding stone exerts sufficient pressure on the shoes 54 to move the ends 23 and 24 a suflicient distance apart to cause the unwinding of the strip 32 a sufiicient amount to rotate the cam 41 and move the plunger 53 from switch open position, as illustrated in Fig. 5, to switch closed position, as illustrated in Fig. 6. Thereupon the machining operation is stopped and the cylinder ID has been machined to accurate dimension, the internal diameter of the bore being gauged externally through the measurement of the diameter of the tool which produced the abrading operation.

t will be seen that through the adjustment of the arms I9 and 2i to have the faces 55 engaged by the abrading stones with a predetermined pressure, the internal diameter of a cylinder may be accurately measured externally by means which interrupt the operation of the abrading tool. The method is unique in that the wearing away of the stones is automatically In tools provided with set means for regulating the degreeof radial expansion of the stones, the wearing of the abrading elements produced errors, and extreme accuracy could not thereby be obtained. In the present instance, the wear on the stones plays no part in the measurement of the cylinder diameter and by external means the diameter is accurately .measured and when desired, the operation of the tool is terminated.

In Fig. 7, we have illustrated diagrammatically the electrical hook-up which be employed for controlling the machine operation. Normally a circuit and ti controls the flow of current to a motor 62 for operating the pump and therefore the tool in reciprocation and rotation. The circuit contains a switch 63 for controlling the flow of current to the motor. When the switch E3 is moved to on position, the abrading operation begins and continues until such time as the switch 52 is operated by the cam 37 to close a circuit 5 3 and 65 to a solenoid {it which moves the switch 63 to off position. This operation immediately collapses the abrading stones of the tool and withdraws the tool from within the cylinder it The collapse of the stones releases the pressure on the faces 55 of the shoes 54. and thereby permits the cam t? to be rotated from switch closing position, as illustrated in Fig. 6, to switch open position as illustrated in Fig. 5, to thereby disconnect the circuit to the solenoid 65. The solenoid however, functions to move the switch 63 to the off position in which position the switch remains until manually operated to on position at the beginning of another cycle of operation. In view of the contraction of the abrading stones they are moved inwardly a suificient amount to be out of engagement with the face of the shoes 5 inwardly of the wiper guides l3 which are recessed a sufficient amount as to avoid striking the faces 55 of the shoes 5G, or at least a suflicient amount to prevent the switch 52 from being operated during the time the body of the tool H is moved from the sleeve I i into the cylinder IE3.

It is to be undertsood that in place of the cam element t! an indicating finger 50 may be provided which would rotate across the face of a scale it to produce visual indication of the bore diameter as it is being machined. The faces 55 of the shoes 54 may engage the stones from the inception of the machining operation so as to be available to gauge the diameter of the bore throughout the entire operation when employed with the cam or the visual indicating means.

While we have described and illustrated several embodiments of our invention, it will be apparent to those skilled in the art, that various changes, omissions, additions and substitutions may be made therein without departing from the spirit and scope of our invention, as set forth in the accompanying claims.

We claim as our invention:

1. The method of machining the internal bore of a cylinder which includes the steps, of expanding abrading elements against the side of the cylinder, reciprocating and rotating the abrading elements as a unit during the time the elements are being expanded to abrade the face of the cylinder, and contacting the abrading elements to measure the diameter of the tool as the elements are reciprocated partially beyond the end of the cylinder bore while the tool is rotating therewithin.

2. The method of machining a cylinder to a predetermined accurate diameter which includes the steps, of rotating and reciprocating an abrading tool within the bore, expanding the abrading elements of the tool during the abrading operation, and directly measuring the diameter of the abrading elements of the tool as they partly project from the end of the bore during a cycle of reciprocating while honing the bore.

3. The method of machining a cylinder to a predetermined accurate diameter which includes the steps, of rotating and reciprocating an abrading tool within the bore, expanding the abrading elements of the tool during the abrading operation, directly measuring the diameter of the abrading elements of the tool as they partly project from the end of the bore during a cycle of reciprocation while rotating Within the bore, and interrupting the machining operation when the external diameter of the abrading elements indicate a predetermined diameter.

4. The combination which includes an abrading tool having a plurality of radially adjustable stones, of means for rotating and reciprocating the abrading tool within a cylinder to be machined, means for expanding the stones during the machining operation, means engaged by the abrading elements as they are partly projected from the end of the cylinder during a cycle of reciprocation While rotating within the cylinder for providing an indication of the diameter of the cylinder being machined.

5. The combination which includes an abrading tool having a plurality of radially adjustable stones, of means for rotating and reciprocating the abrading tool within a cylinder to be machined, means for expanding the stones during the machining operation, means directly measuring the diameter of the abrading elements as they are partly projected from the end of the cylinder during a cycle of reciprocation while rotating Within the cylinder for providing an indication of the diameter of the cylinder being machined, and means actuated by said responsive means to interrupt the operation of the tool.

6. The method of machining a cylinder bore which embodies the steps, of reciprocating a honing tool therewithin in such manner as to have the abrading elements moved from the end of the cylinder an appreciable amount during each cycle of reciprocation, of rotating the tool during said operation in reciprocation, of expanding the abrading elements of the tool during the operation, and of directly measuring the diameter of the tool as it projects from the bore during the operation.

7. The method of machining a cylinder bore which embodies the steps, of reciprocating a honing tool therewithin in such manner as to have the abrading elements moved from the end of the cylinder an appreciable amount during each cycle of reciprocation, of rotating the tool duringsaid operation in reciprocation of expanding the abrading elements of the tool during the operation, of directly measuring the diameter of the tool as it projects from the bore, and interrupting the operation of the tool when the measurement of the diameter of the tool indicates that the desired bore diameter obtains.

8. A gauging device for an internal cylinder bore including, an expansible tool, and means for directly measuring the diameter of the tool during a machining operation.

9. The method of machining a cylinder bore to a predetermined accurate diameter which includes the steps of; rotating and reciprocating an abrading tool having abrading elements which extend beyond the bore, expanding the abrading elements against the side of the bore, and directly measuring the diameter of the tool through the engagement of the abrading elements during the machining operation as the elements project from the bore.

KIRKE W. CONNOR. DOUGLAS T. PEDEN. 

